Rising Mortgage Rates, Potential for More Supply Threaten Pace of Gains Shown in Two Indexes

Home prices during the first half of 2013 posted their largest gain since the housing boom peaked seven years ago, but rising mortgage rates and the potential for more supply could eventually slow the run-up.

Nationally, home values rose by 5.8% in June from one year ago, according to Zillow Inc., the real-estate website, the largest gain since 2006. So far this year, prices are up 2.7%, the strongest year-to-date gain in June since...